This invention relates to the testing of electrochemical storage cells and, more particularly, to a tester having Kelvin contacts which may be automatically secured to the terminals of a cell upon command of a microprocessor.
Electrochemical storage cells or batteries, the term battery applying both to a single cell as well as to a plurality of interconnected cells, are manufactured in large numbers for use in numerous applications in which they serve as the source of electrical power for such diverse items as radios and computers. To insure the reliable operation of such cells, it is the practice among manufacturers of the cells to test the cells before the shipping of the cells to the consumer. In order to facilitate the manufacturing operation, the cells are advantageously tested on the production line in a procedure which involves a minimal amount of time by personnel on the production line.
A problem arises in that the testing of the cells involves both the presence of a high current in the battery terminals and the contacts of the test equipment during one of the tests while, in another of the tests, a sensitive voltage measurement is to be made across the cell terminals. In order to accomplish most of these tests, it is the practice to use Kelvin contacts for the connection of the test equipment to the terminals of the cell. The Kelvin contact permits the implementation of both types of tests so as to eliminate the arduous procedure wherein the battery must be reconnected to test equipment for each of the tests. However, heretofore, the use of the Kelvin contacts on the production line has not been as successful as would be desired. Such contacts have been mounted by springs to insure adequate contact pressure on the cell terminals. But the spring mounting of the contacts has resulted in a lack of accuracy in the positioning of the contacts, as well as excessive wearing of the contacts.